Personally, tests are important to provide a national (Or state-based) standard for students. It's no secret that some schools or classes may actually have an easier time than others - for a varying degree of reasons, some teachers are not as good as others. By eliminating tests (Or allowing those with "high" grades to choose not to write) they are allowing those who may have had an easier class and work load to skip this standard. By providing a test that all students must pass - we ensure that the knowledge base of all students who pass is similar and/or equal in some respects, and so other discrepancies of public education are made up for in some ways. If we don't have this, we are letting those who may have even cheated in course work (Or even those who were not challenged intellectually by their teacher, and are behind the standard of acceptable knowledge) to get by without being tested - putting them on the same, if not higher level, than those who are more intellectually capable in the subject(s) at hand.
With that said, it's your school and your choice, although that could mean your competition for post-secondary out of high school consists of a group of savage barbarians barely capable of synthesizing a coherent sentence.
Teachers won't like it because if they're lazy, it means they are required to teach their students a standard of knowledge - and in doing so, actually effectively doing their job. And they are also pressured to uphold a certain average of capable students when the test is administered, which can be stressful for a teacher.
With all this said, I've decided to help you, because I see the unfair aspects of it - to have your future depending on such a test is ridiculously stressful for a student - and the stress itself may even lead to a student doing worse on the test as a direct result - or maybe even failing. There are other ways public education could be improved to make tests like this unnecessary, but since they won't because the cost and consideration involved would be greater, they choose to make it a test. Effective - and unfair.